Pairing the tradition of a DSLR with contemporary multimedia capabilities, the Leica S3 is a medium format camera characterized by its flexible feature-set and integration within a well-developed system. Featuring a redeveloped 64MP 30 x 45mm CMOS sensor, the S3 offers high-resolution stills shooting along with a 15-stop dynamic range and a wide sensitivity range from ISO 100-50000 to suit working in a variety of conditions. The sensors design also omits an optical low-pass filter in order to realize a high degree of sharpness and clarity. In addition to stills, the sensor also enables DCI 4K and Full HD video recording using the entire width of the sensor for a distinct "medium format look." Additionally, benefitting stills is a phase-detection autofocus system that employs a single cross-type central point for fast and accurate focusing performance.

Complementing the imaging capabilities, the S3 maintains the familiar design traits of previous S System cameras, including a large 0